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Astronomy News

The Cassini spacecraft never fails to disappoint. The latest image released by the ESA shows a false colour image of the violent storm raging at Saturn’s north pole, named the ‘Hexagon’ due to its strange shape. This storm has been raging for decades and boasts speeds of up to 320 km/h. To give you some sense of scale. The centre storm with its hurricane like ‘eye’ is 50 times larger than a hurricane’s eye here on Earth and the white oval shape in the lower right corner is a vortex that measures twice the size of the largest hurricane recorded here on Earth.

Last week there were amazing close-up images of the comet, 67P/Churyumov-Gerasimenko taken by the spacecraft Rosetta as it orbits the comet. Now, the European Space Observatory have released a picture of the comet as viewed from Earth. The comet is very faint as it is still 500 million km from the Sun but the image clearly shows the comet’s tail developing.

This image was constructed from 40 exposures lasting fifty seconds superimposed on each other and then the background stars were removed. …

The exciting Rosetta mission by the European Space Agency is really hotting up. Now that the Rosetta spacecraft has established a triangular orbit around the comet, 67P/Churyumov-Gerasimenko, it has started to look for places to land the Philae landing probe.

Five suitable sites have been identified. The image above shows the comet and the potential landing sites taken from about 100km away.

Rosetta is set to continue to cautiously approach the comet to about 10km and then for yet another first in history for this mission, go ahead and land a probe on the comet to take samples. …

Jupiter’s famous swirling storm, the Great Red Spot appears to be in decline. The storm is the smallest size ever measured. Measurements of the Great Red Spot date back to the 1800s but in 1979 the spot was measured at 14,500 miles by the Voyager probes. Currently, Hubble measures the spot at 10,250 miles. The spot is receding at a rate of 580 miles per year and is now circular is shape. If you haven’t yet seen the Great Red Spot in a telescope now may be a good time before it becomes too small or disappears altogether if the current trend continues.

In June NASA will test fly a saucer shaped spacecraft that will be used to land heavy payloads and humans on Mars in the future. The vehicle will be lifted via a balloon to 120,000 feet and dropped. The saucer’s booster rocket will then fire and lift the vehicle to 180,000 feet at a speed of Mach 4. This simulates the density of the atmosphere and conditions of a landing on Mars. The vehicle, known as the Low-Density Supersonic Decelerator (LDSD) will then inflate a Kevlar tube called a Supersonic Inflatable Aerodynamic Decelerator and an enormous parachute called the Supersonic Disk Sail Parachute to test how the craft will behave during a martian landing. …

The Mars Express has produced this dynamic image of the martian surface. The dark dunes are made from the basaltic volcanic rock. You can see in the picture the prevailing winds have swept the dunes across the steep walled crater, known as Rabe crater that is 108km wide. The dark material has then collapsed into the crater creating this fascinating image of what looks like a black waterfall. This is another image that demonstrates nicely that the surface of Mars is not an unchanging dead place but very dynamic and certainly has a lot more to be discovered.

The Rosetta mission is definitely one to watch this year. The spacecraft is on a mission to intercept the comet 67P/Churyumov-Gerasimenko. This comet has a 6.5 year orbit. Until now the comet hasn't looked much like you or I would expect to see as it was too far from the Sun and so not showing any signs of a tail. But now the comet has come close enough to the Sun that the tail is beginning to form, called a coma. Although, close to the Sun at this stage is still 600 million km away. …

The Venus Express spacecraft has been orbiting Venus for about 8 years and its fuel is beginning to run dry. Between the 18th June to the 11th July the spacecraft will take a daring mission to plunge deeper into the atmosphere of Venus. This will hopefully provide information on not only the deeper atmosphere composition but also how the spacecraft reacts in a more hostile environment. The spacecraft will need to undergo an aerobraking procedure to perform this mission. …

The ESA’s Venus Express spacecraft has taken these unusual images of Venus. The left side is a picture taken of the planet during the Venusian day and the left side is taken during the night. The day side is taken in the visible light spectrum and you can see the Sun’s radiation reflecting off the clouds. On the night side (right) the images are taken in infrared and demonstrate the complicated cloud patterns in Venus’ atmosphere. Great contrasting pictures of a world that is not studied as much as others have been.

The Hubble telescope has taken some incredible images capturing the aurora on Saturn. An aurora occurs when particles in the solar wind affect the magnetic field around a planet. Our own planet exhibits the same phenomenon when a green glow occurs in the night sky. This is known as the northern lights, but occur in the south too.

The bursts of light seen here were very dynamic. Some of the lights travelled three times faster than the 10 hour rotation period of Saturn.

When light has to pass around a massive object, like say, a cluster of galaxies the light path is bent. This bending of the light path creates a magnifying lens that allows us to see more distant objects. The strength of this magnification is being determined by astronomers using the Hubble space telescope. They do this by observing Type 1a supernovae in distant galaxies. Type 1a supernovae are useful because they produce the same level of brightness. So by measuring the observed brightness of the supernovae and comparing it to the known level of brightness they should be able to calculate the distance of the supernovae. …

NASA and the University of California have hit the headlines this week with the results of a 40 year observational study that has shown that the West Antarctica Ice Sheet is in a state of decline that can not be stopped. The glaciers contain enough water to raise the oceans by 1.2 metres. It is thought that this will occur over the next few centuries. NASA is a keeping a close watch on the area and will deploy a fleet of research aircraft this October to monitor the thickness of the glaciers, ice sheets and sea ice.

Up until recently it was thought that star clusters formed when giant gas clouds collapsed. The collapse of the gas increased the density of the gas and eventually stars were born from this. This theory would mean that the first stars to form would be at the centre of the cloud as this is the densest place. However, recent data from NASA’s Chandra X-ray Observatory has found a paradox. The oldest stars, and therefore the first stars, are actually found on the outskirts of the gas clouds. …

No we haven’t landed astronauts on Mars yet. Although you wouldn’t be incorrect for thinking it. The image above is one of the martian simulation areas on earth. This one is in Hawaii. This facility is designed to test how humans might behave in similar hostile environments to that found on Mars. The astronauts will spend four months there with only 12 minutes to shower per week, no fresh food and a 20 minute delay in communicating with base. This is to represent the delay they would experience communicating with Earth from Mars. …

Conjunctions are fun to see on Earth. A conjunction is when two astronomical bodies appear to meet or pass by one another. A regular conjunction is the new moon as it passes between the Sun and Earth. Now thanks to the Mars Express we can observe conjunctions from Mars. The image above shows a conjunction between the martian moon, Phobos and the distant planet, Jupiter. At the time the images were taken the distance between these two solar system bodies was 529 million km, but the spacecraft was only 11,400 km from Phobos. …

The hammering drill aboard NASA’s Curiosity rover on Mars has drilled two holes into the sandstone and collected samples. The drill holes can be seen at the top of the picture. The samples will be sieved and analysed aboard the rover as it travels towards its final destination of Mount Sharp. The fresh hole in the picture is 6.5cm deep and 1.6cm wide. The last rock samples that were drilled revealed evidence of an ancient lakebed and conditions suitabel for microbial life. …

ESA’s Planck spacecraft has produced an image of the Milky Way’s magnetic field. The image was created by measuring polarized light from interstellar dust. Light can be polarized, which means the wave vibrates in a specific direction. This occurs when the light interacts with something. This could be a reflection off a mirror or by a magnetic field. The direction of the vibrations can be used to measure magnetic fields across the Milky Way. This is because spinning dust particles align to the magnetic field and any light hitting the dust particles will become polarized to reflect the non-randomness of the spinning dust particles. …

This beautiful image spanning 10,000km of Saturn’s C (left) and B (right) rings was taken by Cassini. Cassini is the spacecraft that is carrying out missions around Saturn. This image was taken in the Ultraviolet wavelength when Cassini flew closest to the rings. The more blue the rings appear the more pure the water ice is that forms them. As the rings become redder the water ice contains more contaminants.

We still don’t know how Saturn’s rings were formed. Theories suggest they may have formed at the same time as the planet or may have been formed by Saturn’s gravity capturing a passing object.

As amateur astronomers we have a tendency to gaze upward and wonder. The satellites orbiting above us have the opposite perspective and have a tendency to observe the wonders down here. This image is thought to be an ancient molten dome of rock that uplifted, not a meteor impact. This amazing geological wonder is an easily recognised landmark for astronauts aboard the ISS. It is found in the Sahara desert.

The Cassini spacecraft seems to be producing some of the most amazing shots at the moment. After the images of the new Saturnian moon named Peggy and the Earth portrait it has now taken its first picture of another blue planet. This time the target is the ice giant Uranus, the seventh planet from the Sun. Uranus is blue not because of water, like Earth, but because of the methane.